Hyperproduction of ginseng saponin and polysaccharide by high density cultivation of Panax notoginseng cells

Abstract

A high-density culture (HDC) of Panax notoginseng cells for simultaneous production of ginseng saponin (secondary metabolite) and polysaccharide (primary metabolite) was performed in Erlenmeyer flasks. An increase in the initial phosphate concentration up to 3.75 m m was found to be beneficial to the production of these two useful metabolites. The most suitable medium was ascertained to be Murashige and Skoog medium with 1 μ m Cu 2+, 3.75 m m phosphate, and 50 g sucrose l −1. The inoculum size in a range of 2.53–10.2 g dry weight (DW) l −1 had significant effect on the cell growth and metabolite accumulation. By investigating the kinetics and optimizing the environmental conditions of the cell cultures, a cell density of 24 g DW l −1 was obtained in a batch culture. Furthermore, a fedbatch cultivation was attempted to further enhance the cell density and metabolite production. A high cell concentration of 35 g DW l −1 and high production of ginseng saponin (1.57 g l −1) and polysaccharide (5.22 g l −1) were successfully achieved by intermittent feeding of sucrose to keep its medium level below 20 g l −1 in the later part of the cultivation. As observed, the cell sedimentation volume reached almost 100%. The cell density attained may be the upper limit of the suspension cultures of P. notoginseng. The productivities of ginseng saponin and polysaccharide were 2.8 and 3.4-fold higher than those obtained in a conventional batch cultivation.